Nitrogen-containing additives for non-aqueous functional fluids

ABSTRACT

The invention relates to non-aqueous functional fluids which contain at least one compound of formula I ##STR1## wherein X is --O--, --S--, --SO--, --SO 2  --, --C(O)--O-- or --N(R 3 )--, in which R 3  is hydrogen or C 1  -C 12  alkyl, R 1  unsubstituted C 1  -C 4  alkyl or C 2  -C 5  alkyl substituted by one to three hydroxyl groups, R 2  is hydrogen, unsubstituted C 1  -C 4  alkyl or C 2  -C 5  alkyl substituted by one to three hydroxyl groups, with the proviso that at least one of the residues R 1  or R 2  is hydroxy-substituted, and wherein R is C 2  -C 20  -alkyl, a residue --CH 2  --CH(OH)--CH 2  --NR 1  R 2 , in which R 1  and R 2  have their previous significance, or R is C 2  -C 18  alkenyl, C 2  -C 3  alkynyl or C 5  -C 12  cycloalkyl, with the proviso that, when X is --O-- or --C(O)--O--, R is branched C 4  -C 20  alkyl, especially a tertiary alkyl group. 
     The compounds of formula I are very suitable as corrosion inhibitors for non-aqueous functional fluids.

The present invention relates to non-aqueous functional fluids which contain nitrogen-containing compounds, to novel nitrogen-containing compounds and to a process for the preparation of said nitrogen-containing compounds.

In U.S. Pat. No. 2,856,363 there are described compounds of the formula RCH(OH)CH(R')N(Y)R"OH, in which R is C₂ -C₁₂ alkyl, R' is hydrogen or C₂ -C₁₂ alkyl, R" is a C₂ -C₅ hydrocarbon chain and Y is hydrogen or R"--OH. Specifically disclosed compounds are those of formulae C₁₀ H₂₃ --CH(OH)--CH₂ --NH--CH₂ --CH₂ --OH and C₁₀ H₂₃ --CH(OH)--CH₂ --N(CH₂ --CH₂ --OH)₂. The compounds are described as corrosion inhibitors in lubricating oils.

Further, in GB Patent Specification No. 1 152 947 there are described N-(2-hydroxy-3-alkoxypropyl)ethanolamines and N-(2-hydroxy-3-alkoxypropyl)diethanolamines and quaternary ammonium salts thereof as antistatic agents for polymers. In GB Patent Specification No. 979 667 there are described adducts of mono- or dialkanolamines with glycidyl alkyl esters as starting materials in the preparation of polyurethanes.

Furthermore, in GB Patent Specification No. 980 003 there are described 1-N-alkyl- and 1-N-hydroxyalkyl-3-alkylcarboxy-2-propanols and the quaternary ammonium salts thereof for use in cosmetic preparations.

The present invention relates to compositions which contain a non-aqueous functional field and at least one compound of formula I ##STR2## wherein X is --O--, --S--, --SO₂ --, --C(O)--O-- or --N(R³)--, in which R³ is hydrogen or C₁ -C₁₂ alkyl, R¹ is substituted C₁ -C₄ alkyl or C₂ -C₅ alkyl substituted by one to three hydroxyl groups, R² is hydrogen, unsubstituted C₁ -C₄ alkyl or C₂ -C₅ alkyl substituted by one to three hydroxyl groups, with the proviso that at least one of the residues R¹ or R² is hydroxy-substituted, and wherein R is C₂ -C₂₀ alkyl, a residue --CH₂ --CH(OH)--CH₂ --NR¹ R², in which R¹ and R² have their previous significance, or R is C₂ -C₁₈ alkenyl, C₂ -C₃ alkynyl or C₅ -C₁₂ cycloalkyl, with the proviso that, when X is --O-- or --C(O)--O--, R is branched C₄ -C₂₀ alkyl, especially a tertiary alkyl group.

R as C₂ -C₂₀ alkyl may be straight chain or branched alkyl, e.g. ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl or eicosyl, with C₄ -C₂₀ alkyl being preferred, C₈ -C₂₀ alkyl being particularly preferred and C₉ -C₁₂ alkyl being most preferred. R is preferably branched, especially tertiary, alkyl.

R as C₂ -C₁₈ alkenyl may be straight chain or branched alkenyl, e.g. vinyl, n-propenyl, isopropenyl, n-butenyl, isobutenyl, n-pentenyl, n-hexenyl, n-heptenyl, n-octenyl, n-nonenyl, n-decenyl, n-dodecenyl, n-tetradecenyl, n-hexadecenyl or n-octadecenyl, with C₂ -C₄ alkenyl being preferred.

C₂ -C₃ Alkynyl groups are ethynyl or propargyl groups.

C₅ -C₁₂ Cycloalkyl groups are exemplified by cyclopentyl, cyclohexyl, cyclooctyl, cyclodecyl and cyclododecyl groups.

Unsubstituted C₁ -C₁₂ alkyl groups R³ may be straight chain or branched, e.g. methyl, ethyl, n-propyl, n-butyl, n-hexyl, n-octyl, n-decyl, n-dodecyl, isopropyl, t-butyl or t-octyl.

Hydroxy-substituted C₂ -C₅ alkyl groups R¹ and R² are e.g. --CH₂ --CH₂ --OH, --CH₂ --CH₂ --CH₂ --OH, --CH₂ --CH(OH)--CH₃, --CH(CH₂ OH)₂ C₂ H₅ or --C(CH₂ OH)₃, with --CH₂ --CH₂ --OH being preferred.

Examples of compounds of formula I are listed in the following Table 1.

                                      TABLE 1                                      __________________________________________________________________________      ##STR3##                           (I)                                        R         X      R.sup.1    R.sup.2                                            __________________________________________________________________________     i-C.sub.9 H.sub.19                                                                       O      CH.sub.2 CH.sub.2 OH                                                                      H                                                  i-C.sub.9 H.sub.19                                                                       O      CH.sub.2 CH.sub.2 OH                                                                      CH.sub.2 CH.sub.2 OH                               i-C.sub.9 H.sub.19                                                                       O      CH.sub.2 CH(OH)CH.sub.2 OH                                                                CH.sub.2 CH(OH)CH.sub.2 OH                         i-C.sub.12 H.sub.25                                                                      O      CH.sub.2 CH.sub.2 CH.sub.2 OH                                                             CH.sub.2 CH.sub.2 OH                               i-C.sub.12 H.sub.25                                                                      O      CH.sub.2 CH.sub.2 OH                                                                      CH.sub.2 CH(OH)CH.sub.3                            t-C.sub.9 H.sub.19                                                                       S      CH.sub.2 CH.sub.2 OH                                                                      CH.sub.2 CH.sub.2 OH                               t-C.sub.9 H.sub.19                                                                       S      CH.sub.2 CH(OH)CH.sub.2 OH                                                                CH.sub.2 CH(OH)CH.sub.2 OH                         t-C.sub.12 H.sub.25                                                                      S      CH.sub.2 CH.sub.2 OH                                                                      CH.sub.2 CH.sub.2 OH                               t-C.sub.12 H.sub.25                                                                      S      CH.sub.2 CH.sub.2 OH                                                                      CH.sub.2 CH(OH)CH.sub.3                            t-C.sub.16 H.sub.33                                                                      S      CH.sub. 2 CH.sub.2 OH                                                                     CH.sub.2 CH.sub.2 OH                               t-C.sub.16 H.sub.33                                                                      S      C(CH.sub.2 OH).sub.3                                                                      H                                                  t-C.sub.9 H.sub.19                                                                       COO    CH.sub.2 CH.sub.2 OH                                                                      CH.sub.2 CH.sub.2 OH                               t-C.sub.12 H.sub.25                                                                      COO    CH.sub.2 CH.sub.2 OH                                                                      CH.sub.2 CH.sub.2 OH                               n-C.sub.18 H.sub.37                                                                      COO    CH.sub.2 CH.sub.2 OH                                                                      CH.sub.2 CH.sub.2 OH                               n-C.sub.20 H.sub.41                                                                      COO    CH.sub.2 CH.sub.2 OH                                                                      CH.sub.2 CH.sub.2 OH                               C.sub.4 H.sub.9 CH(C.sub.2 H.sub.5)CH.sub.2                                              SO     CH.sub.2 CH.sub.2 OH                                                                      CH.sub.2 CH.sub.2 OH                               C.sub.4 H.sub.9 CH(C.sub.2 H.sub.5)CH.sub.2                                              SO.sub.2                                                                              CH.sub.2 CH.sub.2 OH                                                                      CH.sub.2 CH.sub.2 OH                               n-C.sub.8 H.sub.17                                                                       N(CH.sub.3)                                                                           CH.sub.2 CH.sub.2 OH                                                                      CH.sub.2 CH.sub.2 OH                               i-C.sub.8 H.sub.17                                                                       N(CH.sub.3)                                                                           CH.sub.2 CH.sub.2 OH                                                                      H                                                  t-C.sub.9 H.sub.19                                                                       N(CH.sub.3)                                                                           CH.sub.2 CH(OH)CH.sub.2 OH                                                                CH.sub.2 CH(OH)CH.sub.2 OH                         __________________________________________________________________________

Preferred compositions are those which contain a non-aqueous functional field and at least one compound of formula I, wherein X is --O--, --S-- or --C(O)--O--, as well as those which contain at least one compound of formula I, wherein R¹ and R² are hydroxy-substituted C₂ -C₅ alkyl, especially C₂ -C₄ alkyl monosubstituted by hydroxy. R is preferably C₈ -C₂₀ alkyl, in particular branched C₈ -C₂₀ alkyl, most preferably tertiary C₉ -C₁₂ alkyl.

A further embodiment comprises compositions which contain a non-aqueous functional fluid and at least one compound of formula I, wherein X is --S--, R¹ is hydroxy-substituted C₄ -C₅ alkyl, especially C₄ -C₅ alkyl polysubstituted by hydroxy, and R² is hydrogen and R is C₂ -C₂₀ alkyl, preferably branched C₈ -C₂₀ alkyl, most preferably tertiary C₉ -C₁₈ alkyl.

Some of the compounds of formula I are known and some of the compounds of formula I are novel.

Accordingly, the invention further relates to compounds of formula I ##STR4## wherein X is --O--, --S--, --SO--, --SO₂ --, --C(O)--O-- or --N(R³)--, in which R³ is hydrogen or C₁ -C₁₂ alkyl, R¹ is unsubstituted C₁ -C₄ alkyl or C₂ -C₅ alkyl substituted by one to three hydroxyl groups, R² is hydrogen, unsubstituted C₁ -C₄ alkyl or C₂ -C₅ alkyl substituted by one to three hydroxyl groups, with the proviso that at least one of the residues R¹ or R² is hydroxy-substituted, and wherein R is C₄ -C₂₀ alkyl, a residue --CH₂ --CH(OH)--CH₂ --NR¹ R², in which R¹ and R² have their previous significance, or R is C₂ -C₁₈ alkenyl, C₂ -C₃ alkynyl or C₅ -C₁₂ cycloalkyl, with the proviso that, when X is --O--, --S-- or --N(R³)--, R is branched C₈ -C₂₀ alkyl and, when X is C(O)--O--, R is different from C₄ -C₂₀ alkyl.

Preferred compounds of formula I are those wherein X is --O--, --S-- or --C(O)--O--, and/or R¹ and R² are C₂ -C₅ alkyl monosubstituted by hydroxy.

Especially preferred compounds of formula I are those wherein X is --S-- and/or R is preferably tertiary C₉ -C₁₈ alkyl.

Further preferred compounds of formula I are those wherein X is --S--, R¹ is hydroxy-substituted C₄ -C₅ alkyl, especially C₄ -C₅ alkyl polysubstituted by hydroxy, and R² is hydrogen and R is C₄ -C₂₀ alkyl, preferably C₈ -C₂₀ alkyl, in particular branched C₈ -C₂₀ alkyl, most preferably tertiary C₉ -C₁₈ alkyl.

A further object of the present invention is a process for the preparation of compounds of formula I by reacting a compound of formula II

    R--XH                                                      (II)

wherein X is --O--, --S--, --SO--, SO₂, --C(O)--O-- or --N(R³)--, in which R³ is hydrogen or C₁ -C₁₂ alkyl, and wherein R is C₄ -C₂ alkyl, a residue --CH₂ --CH(OH)--CH₂ --NR¹ R², in which R¹ is unsubstituted C₁ -C₄ alkyl or C₂ -C₅ alkyl substituted by one to three hydroxyl groups, and R² is hydrogen, unsubstituted C₁ -C₄ alkyl or C₂ -C₅ alkyl substituted by one to three hydroxyl groups, with the proviso that at least one of the residues R¹ or R² is hydroxy-substituted, or R is C₂ -C₁₈ alkenyl, C₂ -C₃ alkynyl or C₅ -C₁₂ cycloalkyl, with the proviso that, when X is --O--, --S-- or --N(R³)--, R is branched C₈ -C₂₀ alkyl and, when X is --C(O)--O--, R is different from C₄ -C₂₀ alkyl, or of a metal salt thereof, e.g. the sodium or potassium salt, in the absence or presence of a catalyst, with a compound of formula III ##STR5## to produce a compound of formula IV ##STR6## which is then reacted with an amine of formula V ##STR7## wherein R¹ and R² have their previous significance.

The catalyst may be for example an acid, a base or a phase transfer catalyst.

The known compounds are prepared in analogous manner.

The compounds of formula I are very suitable for improving the properties, especially the corrosion-inhibiting properties in non-aqueous functional fluids.

The compounds of formula I are employed as corrosion inhibitors in non-aqueous functional fluids in amounts of 0.001 to 5% by weight, especially 0.05 to 3% by weight, based on the non-aqueous functional fluid.

The non-aqueous functional fluid may be a lubricating oil e.g. a natural or synthetic lubricating oil; a refined petroleum product such as a fuel oil, diesel oil, kerosene, gasoline or aviation fuel; or a hydraulic fluid, e.g. a phosphate-based synthetic oil.

The lubricating oil may be a mineral oil, a synthetic oil or any mixture of such oils. Mineral oils are preferred and examples of these include paraffin oils, e.g. a mineral oil having a viscosity of 46 mm² /s at 40° C.; "150 Solvent Neutral", a solvent refined neutral mineral oil having a viscosity of 32 mm² /s at 40° C.; and "Solvent brightstocks", a high-boiling residue from the process of refining mineral oil, and having a viscosity of 46 mm² /s at 40° C.

Synthetic lubricating oils which may be present are for example synthetic hydrocarbons such as polybutene, alkyl benzenes and poly-alpha olefins as well as simple di-, tri- and tetraesters, complex esters and polyesters. Diesters are derived e.g. from carboxylic acid esters of the formula

    R.sup.5 --O(O)C--alkylene--C(O)O--R.sup.4

wherein "alkylene" is a C₂ -C₁₄ alkylene residue and R⁴ and R⁵ are the same or different and each is a C₆ -C₁₈ alkyl group.

Triesters which may be used as lubricating oil base-stocks are those derived from trimethylolpropane and C₆ -C₁₈ monocarboxylic acids or mixtures thereof, whereas suitable tetraesters include e.g. those derived from pentaerythritol and a C₆ -C₁₈ monocarboxylic acid or mixtures thereof.

Complex esters suitable for use as components of the compositions of the present invention are e.g. those derived from monobasic acids, dibasic acids and polyhydric alcohols, for instance the complex ester derived from trimethylolpropane, caprylic acid and sebacic acid.

Suitable polyesters are e.g. those derived from a C₄ -C₁₄ dicarboxylic acid and at least one aliphatic dihydric C₃ -C₁₂ alcohol, e.g. those derived from azelaic acid or sebacic acid and 2,2,4-trimethylhexane-1,6-diol.

The lubricating oils can also contain other additives which may be added to improve the basic properties of lubricants, e.g. antioxidants, metal passivators, rust inhibitors, viscosity-index improvers, pour-point depressants, dispersing agents, emusifiers, extreme pressure additives and anti-wear additives. Examples of such additives are indicated below.

EXAMPLES OF PHENOLIC ANTIOXIDANTS

1. Alkylated monophenols

2,6-di-tert-butyl-4-methylphenol

2,6-di-tert-butylphenol

2-tert-butyl-4,6-dimethylphenol

2,6-di-tert-butyl-4-ethylphenol

2,6-di-tert-butyl-4-ethylphenol

2,6-di-tert-butyl-4-n-butylphenol

2,6-di-tert-butyl-4-isobutylphenol

2,6-dicyclopentyl-4-methylphenol

2-(α-methylcyclohexyl)-4,6-dimethylphenol

2,6-dioctadecyl-4-methylphenol

2,4,6-tricyclohexylphenol

2,6-di-tert-butyl-4-methoxymethylphenol

o-tert-butylphenol

2. Alkylated hydroquinones

2,6-di-tert-butyl-4-methoxyphenol

2,5-di-tert-butylhydroquinone

2,5-di-tert-amylhydroquinone

2,6-diphenyl-4-octadecyloxyphenol

3. Hydroxylated thiodiphenyl ethers

2,2'-thiobis(6-tert-butyl-4-methylphenol)

2,2'-thiobis(4-octylphenol)

4,4'-thiobis(6-tert-butyl-3-methylphenol)

4,4'-thiobis(6-tert-butyl-2-methylphenol)

4. Alkylidenebisphenols

2,2'-methylenebis(6-tert-butyl-4-methylphenol)

2,2'-methylenebis(6-tert-butyl-4-ethylphenol)

2,2'-methylenebis[4-methyl-6-(α-methylcyclohexyl)phenol]

2,2'-methylenebis(4-methyl-6-cyclohexylphenol)

2,2'-methylenebis(6-nonyl-4-methylphenol)

2,2'-methylenebis(4,6-di-tert-butylphenol)

2,2'-ethylidenebis(4,6-di-tert-butylphenol)

2,2'-ethylidenebis(6-tert-butyl-4-isobutylphenol)

2,2'-methylenebis[6-(α-methylbenzyl)-4-nonylphenol]

2,2'-methylenebis[6-(α,α-dimethylbenzyl)-4-nonylphenol]

4,4'-methylenebis(2,6-di-tert-butylphenol)

4,4'-methylenebis(6-tert-butyl-2-methylphenol)

1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)butane

2,6-di(3-tert-butyl-5-methyl-2-hydroxybenzyl)-4-methylphenol

1,1,3-tris(5-tert-butyl-4-hydroxy-2-methylphenyl)-3-n-dodecylmercaptobutane

ethylene glycol bis[3,3-bis(3'-tert-butyl-4'-hydroxyphenyl)butyrate]

di(3-tert-butyl-4-hydroxy-5-methylphenyl)dicyclopentadiene

di[2-(3'-tert-butyl-2'-hydroxy-5'-methylbenzyl)-6-tert-butyl-4-methylphenyl]terephthalate.

5. Benzyl compounds

1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene

di(3,5-di-tert-butyl-4-hydroxybenzyl)sulfide

3,5-di-tert-butyl-4-hydroxybenzylmercaptoacetic acid isooctyl ester

bis(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)dithioterephthalate

1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate

1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate

3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid dioctadecyl ester 3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid monoethyl ester calcium salt.

6. Acylaminophenols

4-hydroxylauric acid anilide

4-hydroxystearic adid anilide

2,4-bis-octylmercapto-6-(3,5-di-tert-butyl-4-hydroxyanilino)-s-triazine

N-(3,5-di-tert-butyl-4-hydroxyphenyl)carbamic acid octyl ester.

7. Esters of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid with mono- or polyhydric alcohols, e.g. with

    ______________________________________                                         methanol       diethylene glycol                                               octadecanol    triethylene glycol                                              1,6-hexanediol pentaerythritol                                                 neopentyl glycol                                                                              tris(hydroxyethyl) isocyanurate                                 thiodiethylene glycol                                                                         di(hydroxyethyl) oxalic acid diamide                            ______________________________________                                    

8. Esters of β-(5-tert-butyl-4-hydroxy-3-methylphenyl)propionic adid with mono- or polyhydric alcohols, e.g. with

    ______________________________________                                         methanol       diethylene glycol                                               octadecanol    triethylene glycol                                              1,6-hexanediol pentaerythritol                                                 neopentyl glycol                                                                              tris(hydroxyethyl) isocyanurate                                 thiodiethylene glycol                                                                         di(hydroxyethyl) oxalic acid diamide                            ______________________________________                                    

9. Amides of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid e.g.

N,N'-di(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexamethylenediamine

N,N'-di(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)trimethylenediamine

N,N'-di(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazine.

Examples of amine antioxidants:

N,N'-diisopropyl-p-phenylenediamine

N,N'-di-sec-butyl-p-phenylenediamine

N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine

N,N'-bis(1-ethyl-3-methylpentyl)-p-phenylenediamine

N,N'-bis(1-methylheptyl)-p-phenylenediamine

N,N'-diphenyl-p-phenylenediamine

N,N'-di(naphthyl-2)-p-phenylenediamine

N-isopropyl-N'-phenyl-p-phenylenediamine

N-(1,3-dimethylbutyl)-N'-phenyl-n-phenylenediamine

N-(1-methylheptyl)-N'-phenyl-p-phenylenediamine

N-cyclohexyl-N'-phenyl-p-phenylenediamine

4-(p-toluenesulfonamido)diphenylamine

N,N'-dimethyl-N,N'-di-sec-butyl-p-phenylenediamine

diphenylamine

4-isopropoxydiphenylamine

N-phenyl-1-naphthylamine

N-phenyl-2-naphthylamine

octylated diphenylamine

4-n-butylaminophenol

4-butyrylaminophenol

4-nonanoylaminophenol

4-dodecanoylaminophenol

4-octadecanoylaminophenol

di-(4-methoxyphenyl)amine

2,6-di-tert-butyl-4-dimethylaminomethylphenol

2,4'-diaminodiphenylmethane

4,4'-diaminophenylmethane

N,N,N',N'-tetramethyl-4,4'-diaminodiphenylmethane

1,2-di[(2-methylphenyl)amino]ethane

1,2-di(phenylamino)propane

(o-tolyl)biguanide

di[4-(1',3'-dimethylbutyl)phenyl]amine

tert-octylated N-phenyl-1-naphthylamino

mixture of mono- and dialkylated tert-butyl-/tert-octyldiphenylamines.

Examples of metal passivators are: for copper, e.g.: triazole, benzotriazole and their derivates, 2-mercaptobenzothiazole, 2,5-dimercaptothiadiazole, salicylidenepropylenediamine, salts of salicylaminoguanidine.

Examples of rust inhibitors are:

(a) organic acids, their esters, metal salts and anhydrides, e.g.: N-oleoyl sarcosine, sorbitan mono-oleate, lead naphthenate, dodecenylsuccinic anhydride, alkenylsuccinic acid half esters, 4-nonylphenoxyacetic acid;

(b) nitrogen-containing compounds, e.g.:

(I) primary, secondary or tertiary aliphatic or cycloaliphatic amines and amine salts of organic and inorganic acids, e.g. oil-soluble alkylammonium carboxylates; and

(II) heterocyclic compounds, e.g.: substituted imidazolines and oxazolines.

(c) phosphorus-containing compounds, e.g.: amine salts of phosphoric acid partial esters

(d) sulfur-containing compounds, e.g.: barium dinonyl naphthalene sulfonates and calcium petroleum sulfonates.

Examples of viscosity-index improvers are: polymethacrylates, vinylpyrrolidone/methacrylate copolymers, polybutenes, olefin copolymers, styrene/acrylate copolymers.

Examples of pour-point depressants are: polymethylacrylates and alkylated naphthalene derivatives.

Examples of dispersing agents/surfactants are: polybutenylsuccinic acid imides, polybutenylphosphonic acid derivatives, and basic Mg, Ca and Ba sulfonates and Mg, Ca and Ba phenolates.

Examples of anti-wear additives are: compounds containing sulfur and/or phosphorus and/or halogen, e.g.: sulfurised vegetable oils, zinc dialkyl dithiophosphates, tritolyl phosphate, chlorinated paraffins, alkyl disulfides and aryl disulfides.

The compounds of formula I are useful as additives in particular to lubricating systems, especially engine oils, in which they exhibit corrosion-inhibiting properties. Relative to known compounds having comparable properties, the compounds of formula I are advantageous in that they are phosphorus- and tin-free so that not even the after-combustion of the exhaust gas is impaired.

EXAMPLE 1

10.5 parts of diethanolamine are added dropwise on to 22.8 parts of glycidyl tert-decanoate at 60° C. and the resultant solution is stirred for 3 hours. The crude product is distilled to give 28.1 parts of N,N-di(hydroxyethyl)-2-hydroxy-3-tert-nonylcarbonyloxypropylamine. Boiling point: 225° C./0.13 mb.

EXAMPLE 2

10.5 parts of diethanolamine are heated to 60° C. and 27.1 parts of tert-dodecylglycidyl thioether are added dropwise. After completion of the addition, the mixture is stirred for 1 hour at 70° C. 3-tert-Dodecylthio-1-[di(2-hydroxyethyl)amino]propan-2-ol is obtained as a yellow viscous liquid having refractive index n_(D) ²⁰ =1.4972 in a yield of 100% of theory.

EXAMPLE 3

By following a procedure analogous to that of Example 2, 21 parts of diethanolamine are reacted with 45.4 parts of tert-nonylglycidyl thioether to produce 3-tert-nonylthio-1-[di(2-hydroxyethyl)amino]propan-2-ol as a yellow viscous liquid having refractive index n_(D) ²⁰ =1.5008 in a yield of 100% of theory.

EXAMPLES 4 TO 21

Further compounds of formula I ##STR8## are prepared by following a procedure analogous to those of Examples 1 and 2. These compounds are listed to Table 2.

                                      TABLE 2                                      __________________________________________________________________________     Ex.                                                                               R             X             R.sup.1  R.sup.2 b.p. (°C.)/mb           __________________________________________________________________________      4 t-C.sub.9 H.sub.19                                                                           COO           (CH.sub.2).sub.3 OH                                                                     (CH.sub.2).sub.3 OH                                                                    viscous oil                     5 t-C.sub.9 H.sub.19                                                                           COO           CH.sub.3 CH.sub.2 CH.sub.2 OH                                                                   200/0.065                       6 t-C.sub.9 H.sub.19                                                                           COO           CH.sub.2 CHOHCH.sub.3                                                                   CH.sub.2 CHOHCH.sub.3                                                                  200/0.05                        7 i-C.sub.8 H.sub.17                                                                           O             CH.sub.2 CH.sub.2 OH                                                                    CH.sub.2 CH.sub.2 OH                                                                   190/2.34                        8 i-C.sub.8 H.sub.17                                                                           O             (CH.sub.2).sub.3 OH                                                                     (CH.sub.2).sub.3 OH                                                                    viscous oil                     9 i-C.sub.8 H.sub.17                                                                           O             CH.sub.3 CH.sub.2 CH.sub.2 OH                                                                   180/0.065                      10 i-C.sub.8 H.sub.17                                                                           O             CH.sub.2 CHOHCH.sub.3                                                                   CH.sub.2 CHOHCH.sub.3                                                                  180/0.05                       11 CH.sub.2CHCH.sub.2                                                                           O             CH.sub.2 CH.sub.2 OH                                                                    CH.sub.2 CH.sub.2 OH                                                                   210/0.05                       12 C.sub.4 H.sub.9 CH(C.sub.2 H.sub.5)CH.sub.2                                                  N(CH.sub.2 CH(C.sub.4 H.sub.9)C.sub.2 H.sub.5                                                CH.sub.2 CH.sub.2 OH                                                                    CH.sub.2 CH.sub.2 OH                                                                   viscous oil                    13 C.sub.4 H.sub.9 CH(C.sub.2 H.sub.5)CH.sub.2                                                  N(CH.sub.2 CH(C.sub.4 H.sub.9)C.sub.2 H.sub.5)                                               (CH.sub.2).sub.3 OH                                                                     (CH.sub.2).sub.3 OH                                                                    viscous oil                    14                                                                                 ##STR9##     N(C.sub.12 H.sub.25)                                                                         CH.sub.2 CH.sub.2 OH                                                                    CH.sub.2 CH.sub.2 OH                                                                   170/0.35                       15 t-C.sub.9 H.sub.19                                                                           S             CH.sub.2 CH.sub.2 OH                                                                    H                                      16 t-C.sub.9 H.sub.19                                                                           S             CH.sub.3 CH.sub.2 CH.sub.2 OH                   17 t-C.sub.12 H.sub.25                                                                          S             CH.sub.2 CH.sub.2 OH                                                                    CH.sub.2 CH.sub.2 OH                                                                   155/0.16                       18 t-C.sub.9 H.sub.19                                                                           S             CH.sub.2 CH.sub.2 OH                                                                    CH.sub.2 CH.sub.2 OH                   19 t-C.sub.16 H.sub.33                                                                          S             CH.sub.2 CH.sub.2 OH                                                                    CH.sub.2 CH.sub.2 OH                                                                   viscous oil                    20 t-C.sub.9 H.sub.19                                                                           S             C(CH.sub.2 OH).sub.3                                                                    H       m.p. 61-63° C.          21 t-C.sub.12 H.sub. 25                                                                         S             C(CH.sub.2 OH).sub.2 C.sub.2 H.sub.5                                                    H       viscous oil                    22 t-C.sub.16 H.sub.33                                                                          S             C(CH.sub.2 OH).sub.3                                                                    H       viscous oil                    23 t-C.sub.4 H.sub.9                                                                            S             C(CH.sub.2 OH).sub.3                                                                    H                                      24 C.sub.2 H.sub.5                                                                              S             C(CH.sub.2 OH).sub.3                                                                    H                                      __________________________________________________________________________

EXAMPLES 22 TO 28

Several products of Examples 1 to 21 are tested as rust inhibitors in a turbine grade mineral oil of viscosity 26 mm² /g at 40° C., 4.8 mm² /g at 100° C. and a typical sulphur content of 0.6%, using the ASTM D665A (deionised water) and D665B (synthetic sea water) methos. The results are set out in Table 3 and are expressed as the concentration (ppm) of the product which will prevent any trace of rusting of the test spindle. In both A and B tests, the absence of additive causes severe rusting of the test spindle to occur.

                  TABLE 3                                                          ______________________________________                                         Exam-              Minimum concentration for zero rust                         ple   Test compound                                                                               A test ppm   B test ppm                                     ______________________________________                                         22    Product of Ex. 1                                                                            <250         <250                                           23    Product of Ex. 4          <500                                           24    Product of Ex. 7                                                                            <125         <125                                           25    Product of Ex. 8          <500                                           26    Product of Ex. 2          <500                                           27    Product of Ex. 3                                                                            <125         <125                                           28    Product of Ex. 15                                                                           <250         <500                                           ______________________________________                                     

What is claimed is:
 1. A composition, having corrosion inhibiting properties, which comprises(a) a non-aqueous functional liquid, and (b) an effective corrosion-inhibiting amount of at least one compound of formula I ##STR10## wherein X is --COO--, R¹ is unsubstituted C₁ -C₄ -alkyl or C₂ -C₅ -alkyl substituted by one to three hydroxyl groups, R² is hydrogen, unsubstituted C₁ -C₄ -alkyl or C₂ -C₅ -alkyl substituted by one to three hydroxyl groups, with the proviso that at least one of the residues R¹ or R² is hydroxy-substituted, and R is branched C₄ -C₂₀ -alkyl, C₂ -C₁₈ -alkenyl, C₂ -C₃ -alkynyl or C₅ -C₁₂ -cycloalkyl.
 2. A composition according to claim 1, wherein in formula I R is C₈ -C₂₀ alkyl.
 3. A composition according to claim 2, wherein in formula I R is C₉ -C₁₂ alkyl.
 4. A composition according to claim 1, wherein in formula I R is tertiary C₄ -C₂₀ alkyl.
 5. A composition according to claim 1, wherein in formula I R¹ and R² are C₂ -C₅ alkyl monosubstituted by hydroxy.
 6. A composition according to claim 1, wherein the non-aqueous functional fluid is a lubricating oil, a refined petroleum product or a hydraulic fluid.
 7. A composition according to claim 6, wherein the lubricating oil is a mineral oil.
 8. A composition according to claim 6, wherein the hydraulic fluid is a synthetic oil.
 9. A composition according to claim 1, wherein the amount of compound of formula I is 0.001 to 5% by weight, based on the non-aqueous functional fluid.
 10. A composition according to claim 6, wherein the functional fluid contains further additives selected from the group consisting of antioxidants, metal passivators, rust inhibitors, viscosity-index improvers, pour-point depressants, dispersing agents, emulsifiers, extreme pressure additives or anti-wear additives. 